1. Field of the Invention
The present invention relates to a light source control device for controlling a light source.
2. Description of the Related Art
Over recent years, semiconductor light sources, such as light emitting diodes (LEDs), featuring longer operating life and low power consumption have been in use in substitution for the conventional halogen lamps having filaments. The degree of luminescence, namely the brightness, of LED depends on the amount of electric current supplied to the LED. For this reason, a lighting circuit for regulating the current flowing through the LED is required when the LED is utilized as the light source.
In Patent Document 1 in the following Related Art Documents, the present applicant proposes the technology where for the purpose of varying the light distribution of a headlamp and performing a fine-tuned control of light distribution, an array of LEDs are employed as the light sources, and these LEDs are separately turned on and off. In the lighting circuit cited in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2011-192865), a bypass switch is provided in parallel for each LED, and the on/off of the respective bypass switches individually turn on/off the respective LEDs.
Where such a bypass method as described in Patent Document 1 is employed, the wiring around the LED gets comparatively complicated. The complicated wiring may increase the chance of the conduction failure such as contact failure and disconnection to occur.